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Prices (during review): 26 900 PLN/pair

Contact: Andreas Friedl
Anton-Afritsch-Weg 4
A-8052 Thal | Austria


Provided for test by: MOJE AUDIO

siris is a small, free-standing loudspeaker made by the Austrian company Trenner & Friedl. It's not the most expensive in its offer, and still following all the basic design objectives of its creators - Peter Trenner and Andreas Friedl.

Firstly, when designing their enclosures T&F used the so-called "Golden Ratio" (Lat. Sectio aurea), in which the section is divided into two parts so that the ratio of the length of the longer ones to the shorter was the same as the entire section's to the longer part. The ratio referred to in the definition, is called the golden number and represents the Greek letter φ (pronounced "Fi"). Its value is approximately 1.618. Among other things, Greek temples were build using this ratio. These proportions give a harmonious body, that makes looking at it highly enjoyable.
T & F didn't want their columns to look ostentatious, however, they wanted them to create a good aesthetic impression. The Osiris speakers while standing in my room had true class, and although small, did not disappear in the room.

Their proportions are one thing, but equally important are the technical details. The cabinets are made of birch plywood of varying thickness , damped with natural wool of Australian sheep and finished with natural veneer. The wide front panel is intended to improve the directivity of transducers, and thus reduce the reflections from the walls of the room. And this in turn has lead to improved tonal balance and imaging.

These loudspeakers look extremely elegant. Their cabinets are tilted slightly to the rear, and even though they look a lot like their bigger brother, Pharoah, they are surely sleeker. At both sides there are two stabilizing bars fixed to the cabinet, each of them equipped with two screws going down through these bars that act as speaker's feet. In the middle of the front wall one usually sees an array of drivers - but not here. As in the other columns of this manufacturer's also here drivers are hidden from our eyes.

The coaxial driver with a paper cone is hidden under black grille flush with the front baffle – that's how these speakers are supposed to play. The membrane has been coated in Austria with several layers of Italian balsamic oil, which is to improve the damping. In its center a short plastic horn is mounted, which improves the directivity of titanium diaphragm tweeter. As you can see, designers wanted to achieve the best phase alignment of the drivers, hence coaxial driver (same type of driver was used for Encore! ENC-5) and tilted front baffle.

φ in the case of the loudspeakers under review means not only their proportions. This ratio has been also applied in the construction of wiring used for Osiris. T & F are not the first nor probably the last company that uses this, 2.400 years old, rule. One of the best-known audio companies that adopted golden ratio for its hallmark is the American brand Cardas. Their cables are used for internal wiring of these speakers, also their speaker terminals that accept only spades are placed on the rear panel.

The above mentioned cables one can not see, just as one can't really see the unique design of Osiris cabinets. These speakers combine bass-reflex design and horn, whose symmetrical port is located on the bottom of the cabinet. The combination of these two techniques is to bring the advantages of both methods, i.e. Ensure better extension at the lower end of the range, but with a better impulse response (the point is to avoid that “boomy” bass effect). Let me repeat once again – these loudspeakers have class.

Owner, designer

Osiris is a point source with a coaxial driver; 6,5 woofer 1" compression driver, horn loaded. The paper cone of the woofer is coated with violin lacquer to make it stiffer, minimize resonances. But since Oil lacquer never gets totally stiff, it does not add extra resonances (like other lacquers do) The radiator of the HF compression driver is made of titanium.

Its a vented box, with a down firing horn/reflex system. This optimizes the matching to the rooms, meaning, it is very easy to place; close to walls or corners, is the best, but it's not problematic to place it a little away from walls. But, of course this always depends on the room and system. We use sheep wool as damping material, Mundorf crossover components (hard wired) and fine Cardas cables and connectors. Cabinet is made of birch plywood. Osiris fills the gap between Art and Pharoah, and finally replaces the Dizzy, which has been out of program since a while.

When designing Osiris the target was to make a kind of Panacea. These speakers should be able to fulfill the most of needs. They should perform well in small rooms but also in larger ones. It should be easy to drive (approx 89dB is a good value for a 17cm woofer system, the impedance is very easy for even tube amps). It should become a music machine, which had priority over all other characteristics.

TRENNER&FRIEDL in "High Fidelity”
  • TEST: Trenner & Friedl ISIS – loudspeakers, see HERE
  • TEST: Trenner & Friedl ART – loudspeakers, see HERE
  • TEST: Trenner & Friedl PHAROAH – loudspeakers, see HERE

  • Recordings used in the test (a selection):

    • Andrzej Kurylewicz Quintet, Go Right, Polskie Nagrania „Muza”/Warner Music Poland 4 64880 9, „Polish Jazz vol. 0”, CD (1963/2016)
    • J.S. Bach, Num Komm’ Der Heiden Heiland, wyk. Edna Stern, Zig-Zag Territories ZZT090104, CD (2008)
    • J.S. Bach, Suite Francaise No. 5, wyk. Piotr Anderszewski, Harmonia Mundi HMA 1951679, CD (1999/2010)
    • Jacques Kuba Séguin, Litania Projekt, Odd Sound, CD (2013)
    • Jeff Lynne’s ELO, Alone in the Universe, Columbia/Sony Music Labels (Japan) SICP-30890, Blu-spec CD2 (2015);
    • John Coltrane, Coltrane, Prestige/Analogue Productions CPRJ 7105 SA, SACD/CD (1956/2012)
    • Marilyn Manson, The Pale Emperor. Tour Edition, Cooking Vinyl/JVCKenwood Victor VIZP-138, CD + DVD (2015)
    • Ptaszyn Wróblewski Septet, Bielska Zadymka Jazzowa, Jazz Forum Records 030, CD (2001)
    • Sławek Jaskułke Trio, On, Sławek Jaskułke, CD (2015);
    • Tame Impala, Currents, Universal Music Australia/Hostess 4730676J, CD (2015);
    Japanese issues available at

    It seems that the term "musical machine" which Andreas used in A few simple words... perfectly describes these loudspeakers. Indeed it is so that when listening to Osiris one forgets about the mechanics behind music reproduction. I'm not talking about the "naturalness" of the sound, because whenever music registration is involved naturalness is arbitrary (whatever you've been told), but of such a form of music presentation, that makes it easy to "forget" that one sits in front of a pair of loudspeakers; listening to the music comes so easy with these speakers.

    Like any "machine", also this one has its own characteristics, its properties, and before it takes us to our goal, we will feel this and that. Do you remember SF films, telling stories about people traveling in time or space? Cases in which we would have to deal with the "zero-crossing", disregarding the very moment of transition are extremely rare. Nevertheless, anyone who wants to get from point A to point B does not hesitate. Osiris also may hit a few bumps on the way, in the sense that they have their own character, and that with them we fell the moment "in between”. But when we finally get there, we immediately forget about any inconvenience that happened along the way.

    In their presentation one can clearly hear the emphasis placed on the range called "projection octave" or frequencies between 600 and 1000Hz. It's the part of the midrange, which determines the vocals, especially their central and upper part. When listening to these loudspeakers after exposure to other models for some time it seems that the lower midrange, bass, and treble are rather withdrawn, that these loudspeakers deliver a “lighter” sound than others. This is not true, it's just a moment "of transition" that allows us to accommodate to a bit different presentation. We think for a moment that this is so, because in the presentation Osiris there is no clear the emphasis on attack of the sound, or the separation of images.

    If I hear it correctly, it's about delivering harmonics compliant with the basic sound, which would be difficult with an emphasis on the leading edge. These loudspeakers sound incredibly coherent, and their sound is so easily and fully absorbed. As if in their performance there was no manipulation. The effect of which I spoke earlier involves the disappearance of any emphasis points intended by designers to attract listeners attention.

    Already after a few hours of exposure to the sound of these speakers one can hear a lot of bass and treble. Actually there is everything in this sound but nothing that could distract listener. I was particularly curious about bass performance. It is quite dry and fast but when needed it is also nicely saturated. It's not particularly well extended, but it works quite well for acoustic instruments. Even such a strong left hand, as on the Nun Komm '... album in Busoni transcription sounded very well. In this transcription the left hand imitates playing on organ pedals, which makes it sounds deeper and more powerful than usual. Trenner showed that perfectly, without adding any 'weight' to it, presenting clearly a difference between right and left hand play, and not shortening the bass.

    It seems that this speakers were designed for this and no other type of music. Not that different genres sound bad. If only you're ready to accept this type of presentation - less aggressive and more coherent, without underlined dynamic contrasts and without space engulfing us – we can listen to any album from our collection. But even then, as soon as one returns to jazz and classics, one shall realize that there is something more to this presentation, some additional value, flavor.

    These are loudspeakers for long listening session, for enjoying performance, not necessarily for trips to hi-fi world. On the contrary, these are very non-hi-fi speakers. They do not extract images, do not serve a wide soundscape, mainly focusing on what's in front of us. This is why the mono recordings sounded so lively, instruments had the right size and nice depth. The whole presentation tasted legato.

    The volume of sound is not very big and in this respect, larger model Pharoah is more capable. A lot will also depend on how speakers are placed in the room. I'm pretty sure these were conceived to be placed close to the wall. The closer I placed them to the shelves of books and CDs, which stands in my room behind speakers, the richer was the lower midrange and the greater the volume of sound. Bass, still fast and without boomy effect, was even more coherent. Double bass, which was previously presented with emphasis placed on wood, now had a low "envelope", conferred to it by a closely placed microphone. Because I enjoyed listening to these speakers more when sitting near them with my ears placed slightly higher than the axes of the drivers, I assume that Osiris will be the perfect for small rooms where nothing else wants to play for either bass rumbles, or there is not enough of it.


    I know from experience that it is not easy to convince music lovers to manufacturer's own vision of sound, especially if it is far from just the current standard. And "naturalness" has actually many names. In Trenner & Friedl loudspeakers' case, not only the Osiris but also other ones, it is closer to how 'naturalness' was understood in the 1930s, 1940s and 1950s. It was not about the lack of coloration, because these were present, nor for the highest perceived dynamics and maximum bandwidth extension; but rather about coherency, about delivering natural harmonics, about the essence of the sound and not just its envelope. I'm not saying that what is offered today is bad, it is not, but surely a well executed idea in question is still extremely attractive, especially if you listen to mostly acoustic instruments and naturally generated sounds.

    These are beautifully crafted small size loudspeakers that are extremely friendly to the eye. They sound coherent and smooth, delivering music in a seemingly relaxed but in fact internally tense (emotionally) manner. You have to listen to them a while before you can free yourself from the urge of looking for traditional attributes of hi-fi sound - which are not bad or wrong themselves, but become so when they replace the music. We can use these loudspeakers with a high-end solid-state amplifier (e.g. Lavardin), and with a good tube amp. Each of them will yield slightly different sonic results. Osiris will do great job in some rooms no other speakers can.

    Osiris is a floor-standing loudspeaker model by Trenner & Friedl. Their cabinet is made of thick birch plywood, veneered and oiled. The cabinet is a combination of bass-reflex and horn, with the outlet on the bottom. By screwing or unscrewing the screws which support speaker, one can adjust the amount of bass. The front baffle and back sides are tilted to the rear. The speakers are quite wide, and the depth of the cabinet is small, so in order to improve the stability one screws wooden bars on the sides of the speaker.

    The coaxial driver used by T&F is modified in house. It is a 170 mm bass-midrange transducer with a paper diaphragm, coated with several layers of balsamic oil. In its center there is a 25 mm Titanium diaphragm tweeter loaded with a plastic horn. Finest crossover elements come from Mundorf. Internal wiring and speaker terminals on the other hand come from Cardas. Terminals are made of pure copper coated with rhodium. Their patented design allows clamping of both spades with equal force.

    Technical parameters (according to manufacturer)

    Frequency range: 38Hz (-6dB) - 3 kHz (-3dB)
    Sensitivity: 88,7dB (2,83V/1m)
    Nominal impedance: 8Ω
    Dimensions: H 850 mm x W 360 mm x D 370 mm
    Weight: 25kg/pc
    Veneers: walnut nature, walnut amaranth, walnut mocca



    - Turntable: AVID HIFI Acutus SP [Custom Version]
    - Cartridges: Miyajima Laboratory KANSUI, review HERE | Miyajima Laboratory SHILABE, review HERE | Miyajima Laboratory ZERO (mono) | Denon DL-103SA, review HERE
    - Phono stage: RCM Audio Sensor Prelude IC, review HERE

    - Compact Disc Player: Ancient Audio AIR V-edition, review HERE
    - Multiformat Player: Cambridge Audio Azur 752BD
    - Line Preamplifier: Polaris III [Custom Version] + AC Regenerator, regular version review (in Polish) HERE
    - Power amplifier: Soulution 710
    - Integrated Amplifier: Leben CS300XS Custom Version, review HERE

    - Stand mount Loudspeakers: Harbeth M40.1 Domestic, review HERE
    - Stands for Harbeths: Acoustic Revive Custom Series Loudspeaker Stands
    - Real-Sound Processor: SPEC RSP-101/GL
    - Integrated Amplifier/Headphone amplifier: Leben CS300XS Custom Version, review HERE
    - Headphones: HIFIMAN HE-6, review HERE | HIFIMAN HE-500, review HERE | HIFIMAN HE-300, review HERE | Sennheiser HD800 | AKG K701, review (in Polish) HERE | Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, version 600 - reviews (in Polish): HERE, HERE, HERE
    - Headphone Stands: Klutz Design CanCans (x 3), review (in Polish) HERE
    - Headphone Cables: Entreq Konstantin 2010/Sennheiser HD800/HIFIMAN HE-500, review HERE

    - Portable Player: HIFIMAN HM-801
    - USB Cables: Acoustic Revive USB-1.0SP (1 m) | Acoustic Revive USB-5.0PL (5 m), review HERE
    - LAN Cables: Acoustic Revive LAN-1.0 PA (kable ) | RLI-1 (filtry), review HERE
    - Router: Liksys WAG320N
    - NAS: Synology DS410j/8 TB
    System I
    - Interconnects: Acrolink Mexcel 7N-DA6300, review HERE | preamplifier-power amplifier: Acrolink 8N-A2080III Evo, review HERE
    - Loudspeaker Cables: Tara Labs Omega Onyx, review (in Polish) HERE
    System II
    - Interconnects: Acoustic Revive RCA-1.0PA | XLR-1.0PA II
    - Loudspeaker Cables: Acoustic Revive SPC-PA

    System I
    - Power Cables: Acrolink Mexcel 7N-PC9300, all system, review HERE
    - Power Distributor: Acoustic Revive RTP-4eu Ultimate, review HERE
    - Power Line: fuse – power cable Oyaide Tunami Nigo (6m) – wall sockets 3 x Furutech FT-SWS (R)
    System II
    - Power Cables: Harmonix X-DC350M2R Improved-Version, review (in Polish) HERE | Oyaide GPX-R (x 4 ), review HERE
    - Power Distributor: Oyaide MTS-4e, review HERE
    - Stolik: SolidBase IV Custom, read HERE/all system
    - Anti-vibration Platforms: Acoustic Revive RAF-48H, review HERE/digital sources | Pro Audio Bono [Custom Version]/headphone amplifier/integrated amplifier, review HERE | Acoustic Revive RST-38H/loudspeakers under review/stands for loudspeakers under review
    - Anti-vibration Feets: Franc Audio Accessories Ceramic Disc/ CD Player/Ayon Polaris II Power Supply /products under review, review HERE | Finite Elemente CeraPuc/ products under review, review HERE | Audio Replas OPT-30HG-SC/PL HR Quartz, review HERE
    - Anti-vibration accsories: Audio Replas CNS-7000SZ/power cable, review HERE
    - Quartz Isolators: Acoustic Revive RIQ-5010/CP-4

    - FM Radio: Tivoli Audio Model One